SANTA CLARA, Calif. (AP) -- The pass rusher in Aldon Smith is getting a little more excited than usual this week.

That's a feeling spreading throughout the San Francisco defense as the 49ers prepare for Monday night's game against the Arizona Cardinals, the only NFC West team to beat the Niners during coach Jim Harbaugh's two seasons here.

Despite another strong season from Smith, the 49ers aren't sacking opposing quarterbacks at the same rate they did last year. But that hasn't prevented San Francisco from leading the NFL in both total defense and passing defense.

There could be plenty of opportunities for sacks against the Cardinals, who have struggled all season to protect quarterbacks Kevin Kolb and John Skelton.

That pair has been dropped 35 times in seven games, by far the most sacks allowed by any team in the league. Skelton, who will start Monday's game, was sacked seven times in last week's loss to the Minnesota Vikings.

That's something that hasn't gone unnoticed by Smith, who set a franchise rookie record last season with 14 sacks and leads the team with 5 1/2 this year.

"We'd all like to have more sacks," Smith said Thursday. "Seeing other people have success getting sacks, I mean that's what I do and that's what we do. So of course it's thumbs up for us."

Smith has half of San Francisco's entire sack total. The 49ers have only three sacks in their past three games and rank 23rd in the NFL in sacks per play - the team's lowest standing in 12 defensive categories recorded by the league.

The 49ers had 42 sacks in 2011, and the havoc created by their pass rush was a key to the team's defensive success. Smith burst onto the scene with an impressive rookie season, but the 49ers also got a consistent push up front from their bookend defensive tackles, All-Pro Justin Smith (7 1/2 sacks last year) and Ray McDonald (5 1/2).

Justin Smith and McDonald have combined for only a half sack so far this season. Outside linebacker Ahmad Brooks (three sacks) is the only 49er besides Aldon Smith with more than one sack this year.

But the lack of sacks belies the strength of San Francisco's pass rush. The pressure up front has been good with Justin Smith and McDonald combining for 47 quarterback hits and 68 pressures even though they haven't been taking quarterbacks to the ground.

"We're ranked (first) in pass defense, and pass rush is part of pass defense," defensive coordinator Vic Fangio said. "So, although we don't have the sack numbers, which a lot of people want to sink their teeth into, that's not the measure of a good pass rush. And right now to this point, I haven't seen pass rush as being a weakness for us."

Aldon Smith still has been getting his sacks. He was particularly impressive during a three-play sequence in the final two minutes last week against Seattle to help the 49ers finish a 13-6 victory over the Seahawks that left San Francisco (5-2) a game ahead of Seattle (4-3) and Arizona (4-3) in the division.

With the Seahawks back deep in their own territory, Smith overpowered Seattle offensive tackle Breno Giacomini to sack quarterback Russell Wilson for a seven-yard loss.

Two plays later, with Seattle facing 4th and 17 from its 4, Smith again was pushing Giacomini back into Wilson in the end zone before guard Paul McQuistan peeled back to help. McQuistan was flagged for a chop block on Smith, and the 49ers were awarded a safety that Harbaugh declined since the ball went back to San Francisco with 43 seconds remaining.

"I think teams are a little bit more prepared for us than they were last year and quarterbacks are getting the ball out faster," Smith said. "But all in all we're hurrying throws and we're creating a lot of pressure, so we're doing our job."